1) Class 2) Class ulvophyceae 
The Ulvophyceae or ulvophytes are a class of green algae, distinguished mainly on the basis of ultrastructural morphology, life cycle and molecular phylogenetic data. The sea lettuce, Ulva, belongs here. Other well-known members include Caulerpa and Acetabularia. The Ulvophytes are diverse in their morphology and their habitat. Most are seaweeds s...
(from the article `algae`) ...PleurastrophyceaeFreshwater and marine; includes marine flagellate Tetraselmis.Class UlvophyceaePrimarily marine; includes sea lettuce ...
[n] - alternative name for the class Chlorophyceae in some classifications
class Ulvophyceae noun alternative name for the class Chlorophyceae in some classifications